We propose to collect diffraction data on four projects from our laboratory: ornithine decarboxylase (mODC) from mouse, biosynthetic arginine decarboxylase (bADC) from Escherichia coli (E. coli), the truncated (yeast tE2) components of the pyruvate dehydrogenase complex from Sacchromyces cerevisiae, and the tE2 from the a-ketoglutarate dehydrogenase complex from E. Coli. Data collection of a select group of heavy metal derivatives for both mODC and bADC would aid in the structural determination of these two enzymes.